Is it possible to use zpool create one a full disk, whilst specifying the main partition size? My main use case would be to setup the partitions slightly smaller than the entire disk, so that I know any disks of the "same" size that I happen to purchase as replacements later on will be large enough to hold the ZFS partition. Eg, create a main 998Gb partition on 1TB hard disks.I set a couple of disk up this way manually, formatting with diskutil, and it worked ok but I wasn't convinced that I'd created the partitions correctly. I'd rather have them structured/labelled as per the zpool create command.I suppose the easier way is just to get the formatting/labelling correct via diskutil - any advice?For an 8GB memory stick I was using:

But I don't know how I should specify the 2nd partition. I don't know where the name (something like 6A945A3B-1DD2-11B2-99A6-080020736631) comes from, or what format it should be, or how to make it occupy the remaining disk space.

Lundman's advice is probably the way to go (he should know!), but if you want to control how partitions are set up at the lowest level there is also the option of using the Terminal command 'gpt'. It's very straightforward to use, and you can look it up with 'man gpt'. Here are my notes from when I was setting up my ZFS pool with encrypted 2 TB disks. WARNING: don't apply these commands blindly - the disk you intend to work with might not be disk3, it might be something else!

Setting up partitions, using the example of disk3:

First, unmount any disk partitions on the disk that are currently mounted.

Then destroy the current partition scheme on that disk (WARNING: this command WILL destroy data - do you have backups? Are you sure which disk is which?):